Hi all
My customer is using the DRV8955, they are controlling the input pin by an FPGA, this works fine:
For an input of 3.3V the output is 24V
For an input of 0V the output is 0V.
If they have a resistive load with a current higher than the selected limit they are not getting an nFault.
Their idea is to use the DRV8955 as a "kind of eFuse" to switch off if the output current is > 300mA.
Can you comment and review the below schematic ?
Thank you and best regards
Ueli
Hi Ue,
The schematic is fine to me. There are no obvious issues I can observe.
If they have a resistive load with a current higher than the selected limit they are not getting an nFault
I think you are mistaking current regulation with over-current protection (this article explains the difference between the two). In short explanation, the nFAULT pin does not report anything when the device enters current regulation. It only reports during an OCP event, when the output current is above the IOCP threshold (4-A in your case). Below is the fault condition summary for this device for your information.
Hello Ryan,
Yes we see something different.
We increased the current up to 2.5A and the current isn't regulated.
Attached you can see the current measurement with a current probe.
As load was a 10Ohm Resistor connected between the Output and GND
Regards
Christof
Hi Pablo,
I set IN1 to a PWM Signal of 20kHz and 50% duty cycle.
In the Picture you can see the measurement.
As you can see in the measurement it doesn't regulate the current
Yellow Channel: IN1
Green Channel: OUT1
Orange Channel: Output Current
